1. Field of the Invention
The present invention relates to medical implements, and optical materials, formed essentially of a thermoplastic norbornene polymer. In more particular, it relates to medical implements, and compositions with excellent adhesive property, formed essentially of a thermoplastic norbornene polymer which does not cause the deterioration of medical agents that come into contact therewith, and optical materials formed essentially thereof.
2. Related Art
Medical implements are recently shifting toward those of disposable type in order to prevent secondary infections by various viruses caused by their repeated use. With regard to injection drugs, for example, though they were previously used after sucked into a syringe from a sterilized ampoule at the time of injection, recently prefilled syringes, into which an injection drug has been sucked in advance, have come into wide use and the syringes after injection have come to be discarded.
Medical containers for drugs require transparency higher than a certain degree to allow easy visual confirmation of the contents. Previously, glass, polyethylene, polypropylene, and poly(vinyl chloride) have mainly been used therefore. However, glass is fragile, heavy, and alkali ions tend to dissolve out therefrom. Further, it often causes difficulties in throwaway uses because glass is difficult to burn away and its broken pieces are danger to dispose of. Polyethylene and polypropylene are poor in heat resistance, hence cannot be steam-sterilized, and further sometimes low molecular organic components dissolve out therefrom. Poly(vinyl chloride) is poor in heat resistance, and chlorine tends to dissolve out into the content to cause its deterioration.
On the other hand, poly(methyl methacrylate) (PPMA) and polycarbonate (PC) are known to be used as optical materials. However, though PMMA is excellent in transparency it is rather unsatisfactory in heat resistance and moisture resistance, whereas PC is more excellent in heat resistance and moisture resistance than PMMA, but it has a defect of high birefringence. Accordingly, thermoplastic saturated norbornene polymers, which are excellent in all the properties of transparency, heat resistance, moisture resistance and low birefringence, have come to attract attention as optical materials.
However, thermoplastic saturated norbornene polymers have a problem in that, when used as optical materials, they show poor adhesion to adhesives, coating materials used for coloring, ultraviolet curable coating materials used for protective coating or for forming fine structures, various kinds of inorganic or organic film, and like materials. Various treatments with primes and chemicals as well as actinic energy ray treatments have been studied for the purpose of improving adhesiveness. Addition of these treatments to the steps of production or fabrication of molded articles, however, is unfavorable from the viewpoint of production efficiency.
Accordingly, some attempts have been made to improve the adhesiveness of thermoplastic saturated norbornene polymers by modification of the polymer or incorporation of compounding ingredients into the polymer.
For example, it is disclosed to graft-polymerize 1-40% by weight of a rubber-like polymer to a thermoplastic saturated norbornene polymer (Japanese Patent Kokai (Laid-open) No. 3-54220). This method, however, is not satisfactory in point of production efficiency. Moreover, the polymers obtainable are not always transparent.
It is also disclosed that addition of 1-50% by weight of a rubber-like polymer to a thermoplastic saturated norbornene polymer can give a composition with increased adhesiveness to metals and that the composition can be made transparent by using a rubber-like polymer that has a refractive index near to that of the norbornene polymer (Japanese Patent Kokai (Laid-open) No. 3-112646). In this case, however, a large amount of a rubber-like polymer must be added to a thermoplastic norbornene polymer, which causes a problem of lowering of the glass transition temperature (Tg).